Under the backgrounds such as the increased carbon dioxide emissions due to the consumption of fossil fuels and the dramatic fluctuations of crude oil price, the technical development to shift the energy source of the vehicle from gasoline and diesel oil to electric energy, attracts attention. The electric vehicle is proceeding to practical use, and high capacity and high energy density of a lithium ion battery which is a storage battery, is required for a long distance driving. However, currently a lithium ion battery has a disadvantage of having a difficulty in a long distance driving due to a limited battery capacity. Therefore, a lithium air battery which theoretically has higher capacity than a lithium ion battery, and high energy density, attracts attention. More specifically, a lithium air battery theoretically has an energy density of 3000 Wh/kg or more, which corresponds to about 10 times of the energy density of a lithium ion battery. Besides, a lithium air battery is environmentally friendly, and may provide an improved safety as compared to a lithium ion battery.
Such lithium air battery includes an anode enabling adsorption and discharge of lithium ion; a cathode using oxygen in the air as the active material and containing oxidation and reduction catalysts for oxygen; and lithium ion conductive medium (electrolyte) provided between the anode and the cathode.
That is, the lithium air battery uses oxygen in the air as the active material and generates an oxidation-reduction reaction with the oxygen, thereby enabling charging/discharging the battery.
However, in the lithium air battery according to the related art, hydrogen is generated by lithium metal corrosion metal according to the chemical reaction between lithium and moisture (2Li+2H2O=2LiOH+H2) by permeation of moisture into lithium metal forming anode, or chemical reaction with oxygen (4Li+O2→2Li2O) occurs, and as a result, there is a problem that the performance of the lithium air battery is rapidly degraded.
As the related prior art, US Patent Application Publication No. 2011/0091777 entitled “LITHIUM AIR BATTERY” is disclosed.